"Postpartum women sleep less during the early weeks following delivery than during pregnancy and other periods of reproductive age," Dr. Signe Karen Dorheim, of Stavanger University Hospital, and colleagues write in their report. "At the same time, these women have an increased risk of depression."
Dr. Dorheim's group studied 2830 women who delivered at Stavanger University Hospital between October 2005 and September 2006.
The women reported that they slept an average of 6.5 hours per night. After adjusting the data for other significant depression risk factors - including previous sleep problems, being a first-time mother, not exclusively breast-feeding, having a young infant or having a male infant, and stressful life events - poor sleep was still associated with depression.
"Tiredness after delivery may be attributed to lack of sleep, but the reduced daytime energy could also be caused by depression," Dorheim told Reuters Health.
"Women with postpartum depression may also benefit from treatment of sleep problems," she added.
"Having a newborn baby affects the sleep of the whole family," Dorheim added. "However, when a mother is depressed or complaining of excessive daytime tiredness, it may be important for the partner or other close family to offer support with baby care at night time, to allow the mother a night of recovery sleep," she noted.